Automatic preparative gas chromatograph



Aug. 23, 1966 J. M. KAuss ETAL AUTOMATIC PREPARATIVE GAS CHROMATQGRAPH 8Sheets-Sheet 1 Filed March 4, 1963 INVENTORS JAMES M. KAUSS RBA J.PETERS AARON J-MARTIN 44% 4% 19.5 gag AATT%RNEY5 Aug. 23, 1966 J. M.KAuss ETAL 3,267,646

AUTOMATIC PREPARATIVE GAS CHROMATOGRAPH Filed March 4, 1963 8Sheets-Sheet 2 nob , 30b 30f 132 A 1&-

0 30C 0 I33 30a F INVENTORS JAMES M- KAUSS URBAN J. PETERS AARON J.MARTIN %M,=7z zw%ffiflfi ATTORNEYS Aug. 23, 1966 J. M. KAUSS ETAL3,267,646

AUTOMATIC PREPARATIVE GAS CHROMATOGRAPH Filed March 4, 1963 8Sheets-Sheet :5

INVENTORS u l JAMES M. muss w s2 URBAN J. PETERS Q 2 AARON J. MARTINATTORNEYS J. M. KAUSS ET AL AUTOMATIC PREPARATIVE GAS CHROMATOGRAPH Aug.23, 1966 Pued March 4, 1963 S m n 0 SW N mgmw N K P 6 A J 3W w M U A 7Aug. 23, 1966 Flled March 4, 1963 J. M. KAuss ETAL 3,267,646

AUTOMATIC PREPARATIVE GAS CHROMATOGRAPH 8 Sheets-Sheet 5 INVENTORS JAMESM- KAUSS URBAN J- PETERS AARON J. MARTIN ATTORNEYS Aug. 23, 1966 J. M.KAUSS ETAL AUTOMATIC PREPARATIVE GAS CHROMATOGRAPH 8 Sheets-Sheet 6 Flld March 4, 1963 FIG. 9

FIG. 8

INVENTORS JAMES M. KAUSS URBAN J. PETERS AARONJ-MARTIN ATTORNEYi Aug.23, 1966 J. M. KAUSS ETAL AUTOMATIC PREPARATIVE GAS CHROMATOGRAPH 8Sheets-Sheet 7 Filed March 4, 1963 *9 0E uuv 0 0m 0Q 0Q ow I 09 ll UQ 0100 o I om ow o? @901 uuw 0 0m 2 0m ow oo URBAN J. PETERS AARON J.MART|NBY I //Z/z/;, I W/MW ATTORNEYS Aug. 23, 1966 J. M. KAUSS ETAL 3,

AUTOMATIC PREPARATIVE GAS CHROMATOGRAPH Fxled March 4, 1963 8Sheets-Sheet 8 FIG.H

INVENTORS JAMES M- KAUSS URBAN J. PETERS AARON J- MARTIN ATTORNEY5 nitedStates The present invention relates to an automtaic preparative gaschromatograph. It pertains particularly to a gas chromatograph which iscapable of preparing reagent size quantities of various materialsseparated by the principle of gas chromatography.

In recent years, preparative scale gas chromatography has developed as alogical outgrowth of analytical chromatography. As the name implies thisrelatively new technique takes advantage of the high separatingefiiciencies of the gas chromatograph to physically separate and collectuseful quantities of the components present in a sample material. Thecomponents, thus highly purified, are removed from the carrier gas asthey are eluted from the column. The materials so prepared may be usedfor qualitative studies, reaction studies, or they can be marketed asfine chemicals.

Currently, this use of gas chromatography for the separation andisolation of relatively large or macro quantities of material, ascompared with analytical or micro-quantity separations, is becomingincreasingly important. Although, on a small scale, preparative scalechromatography is often used in conjunction with other techniques as anaid in positive, authoritative identification of components, the use ofthe principle for direct production or separation of relatively largerand even marketable quantities of material is becoming relatively moreimportant. The combined use of chromatography with other techniques isstill of interest but apparently is becoming relatively less important.

The invention has particular applications to such matters as thepreparation of spectroscopic solvents or preparation of pure materialsfor reaction studies, and also for the isolation in marketablequantities of rare or valuable materials such as pharmaceuticals. Thepreparation of materials for such purposes requires substantially largersample capacities or throughput than has ordinarily been feasible withgas chromatograph apparatus in the past.

The desired capacities for large scale samples may be obtained, at leastin theory, by direct scale-up of conventional chromatographic apparatus.However, the practical increase possible by this means is limited. Asimple increase in tube or column capacity by increase of its diameter,or by placing multiple columns in parallel, is of course an easy way toincrease throughput. However, there is a rapid decrease in separatingefficiency as the column diameter is increased, especially as theincrease becomes greater. Large increases in throughput bring problemsand complications in control and detection.

According to the present invention, these problems are approached bylimiting the scale-up of the apparatus to the point where resolution isnot seriously affected and then obtaining higher capacity by automaticand continuously repetitive sampling It has been discovered thatconsiderably larger throughput production can be obtained in this mannerthan would be expected by routine consideration of scale-up Toaccomplish substantially greater volume preparation with relativelymoderate scale-up is a prime purpose of the present invention.

According to the present invention, then, it has also been found thatseparating efficiencies reasonably comparable to those of standard smalldiameter analytical columns in gas chromatographs may be obtained withcolatent umns of substantially larger diameter Careful, automaticcontrol of sample introduction tends to improve reliability ofseparations. For example, analytical columns of a size up to threequarters of an inch, internal diameter, and even up to one inch andpossibly larger, may be used without serious loss of separatingefiiciency. At the same time, the total volume of sample materialseparated and of components recovered is increased proportionally more,by automatic, systematic and repetitive injection of identical samples.

Hence, in addition to providing a system wherein the column size may beincreased fairly substantially to increase the overall capacity of theapparatus, it is possible to further increase the yields of theapparatus by making it fully automatic. This makes possible a relativelycontinuous unattended operation of the chromatograph, even overrelatively long periods, for example, overnight or over a weekend. Italso makes it possible to use the apparatus at or near its very highestefficiency for quantitative separation and collection.

While an apparatus, of the type to which this invention pertains, may bedesigned for simple isothermal operation, it is also desirable that itbe capable of use in or with a variable or programmed temperatureoperation. This temperature programming, of course, tends to add to thecomplexity of the system. However, according to the present invention, arelatively simple solution has been worked out. It is found, in fact,that a programmed temperature operation is just as desirable inpreparatory scale work as it is in analytical work and in some caseseven more desirable. As a result, the equipment or apparatus of thisinvention can be used through wide ranges of temperature to accomplishthe improved separations possible with such programming. A furtherobject of the invention, then, is to take advantage of the newly foundpossibility of preparatory scale separation combined with programmedtemperature operation. An ancillary object, which of course followsdirectly, is to increase substantially the versatility of the unit.

In order to obtain maximum versatility in the apparatus, the automaticfeatures of the unit, according to the present invention, are placedsolely under control of the conditions and operations of the separationbeing performed. Reliance is not placed merely on a preset timingdevice. For example, the actual chromatographic peaks, as they appear onthe recorder to indicate arrival of a particular component separatedfrom the sample, are used to trigger and control the componentcollections operations. This requires coordination of a number of majorcomponents. For example, it requires the coordinated use of an automaticsystem for injection and employment of a selective system for collectingthe separated discrete components or fractions. In the present case thelatter may also be automatic. The eflicient use of recording means isinvolved and, of course, in the case of programmed temperatureoperations, the employment of automatic means for controlling or, ifnecessary, cooling the oven system is also involved.

Accordingly, a primary object of the present invention is to provide afully integrated and substantially completely automatic apparatus forseparating and collecting sizable samples of various components of testor sample materials. At the same time, purity is maintained consistentlyhigh with relatively large scale production. All this is accomplished bydesign of a system requiring almost a minimum of attention on the partof operators.

111 brief summary, the equipment or apparatus of the present inventionis an efficient and reliable instrument of Wide versatility capable ofsustained and largely automatic operation over substantial periods oftime. It is particularly useful for isolating and collecting high puritycomponents from mulit-component or sample materials on either laboratoryor a semi-Works scale. Included are such features as a means to adjustthe ratio of column pressure to back pressure, means to segregate one,two, or more, up to six (or more if desired) individual components,means to return automatically to a starting position after the desirednumber of components has been gathered from a particular sample, andmany other features which will be set forth in detail hereinafter. Theapparatus also comprises a combined but separately operable analyticalsystem of small column type with its own flow indicator-controller asWell as its own column and its separate sample injection facilities.

The invention will be more fully understood by reference to a detaileddescription which will next be given in connection with the accompanyingdrawings. In the drawings:

FIGURE 1 is a schematic flow diagram of an instrument made according tothe present invention.

FIG. 2 is a partial front elevational view, with certain parts beingremoved and certain parts being shown only diagrammatically, of anapparatus according to the present invention.

FIGURE 3 is a transverse horizontal sectional view of part of theapparatus of FIGURE 2 taken substantially along the line 3-3 of FIGURE2.

FIGURE 4 is a vertical sectional view of part of the apparatuscomprising the collector manifold and some associated parts, takensubstantially along the line 44 of FIGURE 2.

FIGURE 4A is a fragmentary view taken from the right side of FIGURE 4,showing relative arrangement of some of the sample collecting tubes.

FIGURE 5 is a sectional view through a part of the sample collectingapparatus, taken substantially along the line 4- 1 of FIGURE 2.

FIGURE 6 is a transverse sectional view of the apparatus, taken alongline 6-6 of FIGURE 5, looking in the direction of the arrows.

FIGURE 7 is a horizontal sectional view of the apparatus shown in FIGURE4 taken substantially along the line 77 of said FIGURE 4.

FIGURE 8 is a vertical sectional view through the oven, takensubstantially along the line 8-8 of FIG- UR-E 2.

FIGURE 9 is a view similar to FIGURE 8, showing certain parts in changedpositions.

FIGURES 10A to 10H, inclusive, are chromatogranis taken by the apparatusof the invention, showing the eifect on resolution of various samplesizes.

FIGURE 11 is a diagrammatic front view showing the major operatingcontrols.

Referring first to FIGURE 1, a schematic representation of thepreparation scale gas chromatograph is shown, some parts being somewhatout of scale and certain other parts being represented onlydiagrammatically. This scheme will be described first to outline some ofthe more important elements and aspects of the invention. Certain of thedetailed mechanisms will be described thereafter.

As shown in FIGURE 1, a carrier gas, under appropriate pressure from asupply source, not shown, such as a tank, is supplied through a line 11controlled by a suittable valve 13. This valve 13 is preferably of thefullyopened, fully-closed type, electromagnetically operated toalternatively cut off flow completely or open to full flow position.From valve 13 the carrier gas, in normal major flow, continues onthrough line 15 to another solenoid operated valve 17 of generallysimilar type, but equipped with a connection line ll'g to a pressuregauge G. From here it passes through a line 18 to a control valve 19 andthen through line 21 to check valve 23 and on to a preheater 25. Herethe temperature of the carrier gas is adjusted to the level desired. Thecarrier gas then passes on through lines 27 to a preparative scaleinjection port 29. The samples are supplied to the injector by a isample dispensing or injector device which is adapted to supplyrepetitively and automatically samples of predeterminable but identicalsize or volume over a prolonged period of time. It will be describedfurther, below.

From the sample injection port the carrier gas normally passes into thechromatograph column or columns indicated generally at 39. These columnsare substantially larger in diameter than normal analytical columns,being of preparative scale dimensions. These columns may be made or"various lengths and diameters but preferably are not so large indiameter as to cause serious losses in separating efficiency. In atypical preparative scale apparatus they have been made about inch indiameter and 8 feet long, in U-shape, each leg of the U being 4 feetlong. However, these sizes can be varied widely and columns of /8 inch,/2 inch and 1 inch diameter have been used successfully. The individualcolumns are arranged for connecting in series or parallel, orseriesparallel, as may be desirable for the particular operationinvolved. They may also be used singly if desired.

The metering or measuring of the sample into the carrier gas stream isaccomplished preferably by means of a dispenser or injector mentionedabove, shown at 28. It comprises a pneumatic-hydraulic cylinder with areciprocable injector piston. Force to operate the piston is preferablysupplied by the carrier gas pressure. Carrier gas is connected to enterthe pneumatic side of a diilerential area stepped piston 28' through aline 28 connected to line 21. The pneumatic side of the piston 28' ispreferably substantially greater in area than that of the hydraulicliquid sample piston. Hence, when sample injection begins, there issufficient mechanical advantage in the force of the carrier gas toovercome any back pressure caused when the sample flash vaporizes intothe hot injection chamber. The injection port chamber in unit 29 is keptat a suitable high temperature.

The injector, per se, is shown at 28 and sample flow thereto iscontrolled by a valve 28a, Which connects it selectively to a supplysource 2&5 and to a discharge line 2.30. The latter leads to theinjection port 29. It is provided also with an electrically operatedexhaust valve 28d for the operating gas and a drain valve 282 forremoving liquid residue. The dispenser or sample injector preferably isdesigned to inject any desired quantities from a small fraction of acubic centimeter to a number of cubic centimeters. In a specificexample, it can be adjusted from A to 12 cc. per stroke. In other Words,the ratio of maxnnum to minimum sample size is 50/1 and may be evenhigher, up to /1. The volume is infinitely variable by a simple screwadjustment which determines precisely the sample volume by limiting thelength of the refill stroke of the injector piston. Since the sampleitself is stored in reservoir 28!; which is under carrier gas pressureat all times through line 281, connected to line 28" through a checkvalve 23, the refilling force against the piston insures that the pistonwill draw a full sample on each stroke. The apparatus is so designedthat the largest capacity sample, 12 cc. in the present instance, iscompletely injected in a very short time, for example, in 5 seconds. Theinjector 28, per se, is described in greater detail and claimed in aseparate application Serial No. 256,337, filed February 5, 1963, byJames M. Kauss, now U.S. Patent No. 3,155,289 issued November 3, 196

The injection chamber of port 29 preferably is in the form of a heatedcylindrical vessel which has an empty volume of several times thelargest sample to be injected. Injection port 29 in a specific exampleof apparatus which has been built has an empty volume of about 35 cc. Itis provided with a heating means and controls therefor, or" conventionaltype, to bring and maintain its temperature at a selected level, up to400 C. It is filled with metal shot, preferably of stainless steel, toact as a heat sink. This quickly brings the sample temperature in thechamber to the desired level.

Likewise, the carrier gas preheater is of similar heat capacity tocontrol the temperature of the gas at a desired level. It is similarlyequipped or filled with stainless steel shot which acts as a heat sinkand serves to bring the carrier gas to the desired operating temperaturevery quickly. These heat capacities are sufficient to rapidly vaporizemore than the maximum sample capacity of material supplied to theinjection port by dispenser or injector 28, such as 12 cc. in theexample just cited. The dispenser or injector 28 preferably is notheated because it employs liquid sealing elements which perform betterat ordinary temperatures.

A manual or syringe injection port, not shown, but of well known type,is also provided for injection of samples by hand, e.g., with a syringe,when this is desired. This may be in the form of a septum in the wall ofelement 29.

The vaporized sample, whether injected manually or automatically, goeswith the carrier gas and passes through the column or columns 30. Thesecolumns, indicated individually at 300 to 30f, are incorporated into anoven chamber 31 which can accommodate a variable number of columns. Bythis means they may be heated, or subjected to variable programmedtemperatures, as desired. In this particular installation, as previouslynoted, the chamber accommodates 6 U-shaped columns. Provisions forheating the oven include the blowers 32, FIGURE 2 and electrical heaterswith appropriate controls. The heating means are described more fullybelow. See also FIGURES 8 and 9.

As the carrier gas and the injected sample material pass through thecolumn, the various component materials in the sample are selectivelyadsorbed and then desorbed. The carrier gas, with the desorbedcomponents, emerges from the columns and passes out of the oven 31through a high temperature needle valve 33. This needle valve provides ameans for varying and controlling the back pressure on the system. Theproper ratio of pressure head to back pressure often is important,particularly in large scale separations. A branch line 34 connects tothe pressure gauge G, previously mentioned, which registers both headand back pressure.

The pressure control valve 33 is kept isothermally at or near thetemperature of the detector cell through which the sample next passes.This cell is indicated at 35. A thermal conductivity type detector cellis preferred. It is enclosed within a heated chamber which can becontrolled in temperature from about 100 to 375 C. The back pressurevalve 33 is controlled at the same temperature and may, for convenience,be housed in the same enclosure. The entire flow of carrier gas andseparated components passes through the detector.

In an apparatus of the size and type described so far, the volume ofcarrier gas flow is often more, and may be considerably more, than oneliter per minute. Hence the detector unit 35, which otherwise isconventional in type and forms no part of the present invention, must bespecially designed, so far as capacity is concerned, to operate at thisvolume without undue noise, or electrical disturbance.

From the detector unit the carrier gas and the now separated samplecomponents, as the latter come along, pass through a line 37 to a samplecollecting trap unit which will be described below.

The detector has a reference side which is supplied by a separate andcomplete analytical system. This analytical system, which employs asmall diameter column, is a complete unit in itself. It has its own flowcontroller, its own injection port and its own small diameter column. Itwill now be described.

At the junction indicated at 41, FIGURE 1, a reference flow of carriergas is taken off through a separate line 43 and passed through areference flow controller and indicator 45. From there it passes througha line 47 to an analytical injection port 49 which is comparable to thepreparatory scale injection port 29 except for its size. From theanalytical injection port the analytical sample, in its carrier gas,passes through a line 50 into the analytical column 51 which is alsohoused within the oven. This analytical column is considerably smallerin diameter than the column 30, being of conventional diameter. It maybe packed or coated interiorly (or both) to perform its analyticalfunction in a manner well known in the art. It is indicateddiagrammatically in FIGURES 1 and 2.

From the analytical column the analytical stream passes through line 53and through the reference side of the detector unit 35. The volume ofcarrier gas and sample material is very small and the efiluent stream isordinarily exhausted into the atmosphere through outlet line 54.

This arrangement is very useful for column scouting work. Merely byreversing the detector leads to the recorder with a panel mountedswitch, mentioned below, the preparative system can provide thereference flow for the small analytical column. The instrument is thenuseful for more exact analytical work. This eliminates labor which wouldotherwise be involved in packing and repacking large colunms whiledetermining the best column packing for a given sample. Differentprepacked (or interiorly coated) analytical columns may be kept on handfor various analytical or comparative analytical problems. Theanalytical column also may be used to check the purity of collectedsample components. The manner of their collection will be describedbelow.

The preparative scale samples or components separated in the preparativecolumns pass with the carrier gas through the line 37 to the manifold 61of the collection system. Manifold 61 is arranged for connection with anindexing valve unit, to be described in detail, so that it can pass theindividual separated components each to a separate one of a number oftraps. It can also by-pass the carrier gas, with or without anycomponents, through a by-pass cleanup trap 68 by means of a lineindicated generally at 65. The indexing fraction collecting valve isindicated generally at 67 and is so arranged that a number of separatecomponents to be trapped or collected, up to six in this specificarrangement, can be separately accumulated. In the example shown, thevalve 67 can be indexed successively to 12 consecutive stop positions,including six separate collecting positions and an intermediate by-passposition between each pair of collecting positions. This necessitates atotal of seven outlet connections to the manifold 61, in all, since theby-p'ass positions of the valve are all connected to a single outlet.

Before the first fraction is to be collected, all flow normally passesthrough the by-pa'ss and cleanup trap 63. As component separationbegins, the first peak rises to a preselected point on the recorder,indicating arrival of a component to be trapped. A recorder penactivated switch, not shown in FIGURE 1 but described below, causesappropriate movement of the fraction collecting valve. The valve 67 thenindexes through 30 igth revolution) to the first collection" position,which is shown in FIGURE 1, position number 1. The mechanism foraccomplishing this will be described below.

This operation also closes the normally open by-pass valve 68a as wellas opening the exit valve 1. This permits gas which is trapped in thefirst collector tube or trap A to flow throughout line 69a to the valve67 and then to the atmosphere through exhaust line 68e. All flow fromline 37 and manifold 61 then passes through trap valve unit 1 on theindexing valve 67. The traps A, B, C, etc., are kept at a componentcondensing temperature and the first component is immediately condensedout of the carrier gas and collected in trap A. The traps are allmounted in a refrigerated compartment so that the heated condensiblematerials from the manifold are immediately collected. Baffle meansinside the traps assist in separating condensed material from the 3,2 7carrier. The carrier gas from all the traps eventually passes outthrough exhaust line 63c. Collection in trap A continues until the peakon the recorder drops to the preselected point on its scale.

After the first peak passes the preselected set point on its way downscale, which operation also will be described more fully below, therotary valve makes another 30 rotation step and the flow is againdiverted to the bypass position. This rotation step closes the componenttrap valve unit it and an operating means described below again causesthe by-pass valve 68a to move to its normally open position.

On arrival of a second component at the detector, the valve 67 is againindexed a half-step or 30 to the second collecting position 2. Thisoperation is repeated in similar steps. The by-pass is opened betweenpeaks and closed during the peaks, or during passage of selected partsof peaks to avoid collection or trapping of side band materials. This isrepeated until a maximum of six different individual separatedcomponents have been collected. The flow thus alternates between by-passand collection in a trap, the sequence being first a Dy-pass, thencollection in the first cold trap A, a by-pass again, then collection inthe second cold trap B, a by-pass once more, then a collection in thethird trap C, and so on through traps D, E, and F, the indexing valveopening successively at positions 1, 2, 3, 4, and 6 as six separatepeaks are reached. The valve can be reset manually in case less than sixpeaks are employed. Where it is desirable to start the cycle anewwithout running through all six settings, e.g., where only 1, 2, 3, orup to 5 components are to be collected, the valve will returnautomatically to its zero point or starting position without stoppingidly at positions where there are no peaks.

All valving thus is done on the exit side of each of the traps. Thevalve 67 is not enclosed either in a heated or in a cooled compartmentand thus operates at room temperature. This has the advantage ofeliminating problems of high temperature sealing, due to use of plasticglands, etc.; it also eliminates problems of high temperature valve bodycorrosion. The traps A, B, C, etc., are only open to gas flow while thecarrier gas is flowing through them. The trap fractions thus are notexposed to ambient air or moisture at any time because the traps alwayscontain a carrier gas atmosphere. To prevent any diffusion between trapssimple gravity ball checks are located in the hot manifold as indicatedat 62. These ball checks can Withstand the high temperatures, unlike theseal parts of valve 67. See FIG. 4.

After the last component to be collected from a given sample has beeneluted, the collection valve 67 is reset to its zero position which isalso the injection position for a new sample. In isothermal operationthis resetting operation itself activates the automatic injector ordispenser 28 which then causes another sample to be introduced throughthe preparative scale injection port 29.

As mentioned above, it is usually desirable that the apparatus also becapable of programmed temperature operation. For such operation thesequence of events is slightly different from that just described forisothermal operation.

Assuming that the last peak is being passed, when it has been passed orhas reached the preselected cut-off level, the recorder pen-operatedswitch causes the rotary component collection or indexing valve 67 tomove to the zero or starting position of by-pass between stations 6and 1. However, this does not automatically activate the automaticinjector. Instead, for temperature programming, the temperatureprogrammer to be mentioned further below, continues up scale until thehigh temperature limit has been reached. This limit can be preset from50 to 325 C. and is under control of the heating elements 276, 271,etc., FIGURES 8, 9, and their controls. At the highest temperature pointon the program, a cooling damper is opened, as will be explained. Thetomwas 'a U perature programmer is reversed, and the controller isdriven down scale to the starting point for another pro- 7 grammedtemperature operation.

The essentials of this apparatus are shown, diagrammatically only, inFIGURE 1. A damper speed control is indicated at 72 in the form of a gasilow restricting valve. Its control valve '74 is of the electricallyoperated type but is operated at a controlled rate in closing oropening. A damper opening cylinder 7'6 is provided to control the rateof damper movement and prevent damage to mechanical parts. When thismechanism operates, the blowers 32 will draw air at room temperatureinto the oven chamber 31 through an inlet for ambient'air. Here the airis circulated over the columns and heaters and passes out through anexhaust duct. Thus the oven temperature is quickly lowered. When apreset starting temperature limit, lower than the first, has beenreached the damper 267 closes. The injector 23 then introduces anothersample through the injection port 29. The programmer then starts upscale again and the cycle is repeated. The oven damper operation isshown in more detail in FIGURES 8 and 9 and will be referred to again.

Referring now to FIGURES 2 and 3, it will be seen that the severalcolumns Ma, 3911, 3tlc, etc., are connected in series, as hereinillustrated, by means of the threaded connectors and the U tubes 131,132, 133, etc., at the top. Corresponding connectors, not numbered, areshown at the bottom of FIGURE 2. See also FIGURE 3. Obviously, byinterchanging the connections the tubes can be placed in series or inseries-parallel as desired.

In normal operation carrier gas from the left, FIGURE- l, picks up thesample supplied by the injector 29 and sweeps it through line 29a intothe column assembly 36. After passing through the column the carrier gasand the separated components of the sample pass through the detector andon into the collector. Before being collected they must, of course, bedirected to the appropriate collecting vessel and this function isperformed by the indexing valve mechanism as just described. The detailsof this mechanism will now be explained.

Referring to FIGURE 4, the manifold 61 is shown as being connected to aplurality of outlet lines lll, only one of which is shown in thisfigure. A gravity ball check 62 is provided in the manifold, at eachconnection to a line 161 to prevent reverse flow. This is to protectcollected components in the traps against contamination.

Each. outlet line 161 is connected through a union to a collector tubeinlet line 166. One of these lines conmeets to each of the collectortubes or traps, e.g., that indicated at C in FIGURE 4. Similar lines,not shown, connect to each of the other traps A, B, D, E and F.

As previously indicated, carrier gas normally is trapped within each ofthe tubes A, B, C, etc., and cannot escape as long as the indexingcontrol valve 63 is closed to that tube. Therefore, component materialto be collected cannot enter the collecting traps, nor will the carriergas either, until the proper outlet in the valve 67 is opened. Eachcollector tube or trap has its own outlet 167 concentric with the inlettube 166. Through suitable packings 168, 169, the annular gas outletline 167 from each component trap connects to one of the tubes 69a, or6%, etc. Through a wall mounting 171 each of these is supported by asuitable collar unit 172. Each line 69a, 6912, etc., is connectedthrough a coupling 173, to a fitting 265a, ZtlSb, 2135c, etc., mountedon a plate 210 which constitutes the non-rotary member of valve 67. Eachof these fittings 205a, etc, leads directly to one of the openings 1, 2or 3, etc., FIGURE 1, controlled by the indexing valve assembly; forexample fitting 205a leads to opening 1. However, by-pass line as fromtube 68 goes to valve 680.

The manifold 61 is enclosed within insulation shown at 177, 173, FIGURE4, so that it can be kept hot. An appropriate heating means indicated atH, preferably electrical and controlled by adjustable thermostatcontrols 304, 304a, FIGURE 11, maintains proper temperature of themanifold. It is usually held at the same temperature as the valve 33 andthe detector. To keep the component vaporized, the manifold may beheated to an even higher temperature than the detector if desired. Thetraps A, B, C, etc., are kept cold.

There are, in the specific instrument shown, six sets of connections205a, etc. The indexing valve mechanism comprises the two-way valve 68a,controlled by a cam 181 on cam shaft 180, as best seen in the lower partof FIGURE 7. This valve is held open normally, i.e., except when aseparated component is being collected in a trap. Cam 181 has aflattened portion 182 which allows valve 68a to close only when fiat 182is in or near the down position See FIGURE 6. Each time the cam isdriven, it rotates a half revolution and stops. These stops occuralternately when the flat portion 182 is down, and indexing shaft 201 isin a trap collecting position, and when the part 182 is up and valve 68ais open to by-pass. Indexing shaft 201, which supports rotary valve 67,likewise comes to periodic halts. By-pass flow is normal and continuesuntil cam shaft 180 is again rotated to the fiatdown position, as it isshown in FIGURE 6.

Gearing is provided as indicated at 183, 184, 185 and 186 so thatindexing shaft 201 turns A th turn for each half turn of cam shaft 180,gear ratios being such that the main indexing rotor shaft 201 passesthrough Ms of a revolution for each full revolution of the cam shaft180. The latter is driven by a cyclically driven electric motor with anappropriate clutch so that it stops at each half turn until startedagain by electric control means. This mechanism is indicated generallyat 220, 221, FIGURE 4. It is of standard commercial type, so far asclutch, motor and starting controls are concerned, and is not describedin detail since it forms no part of the present invention.

During rotation of the cam shaft 180, the peripheral portion of the camholds the cam follower 192 down until the flat portion 182 is again atthe bottom. It then permits the follower to rise under influence of avalve closing spring mechanism, not shown. In its normal stop positionfor collecting component material in a trap the flat surface 182 is downand the follower 192 rises to its upper position. This movement closesthe gas exit for the by-pass trap so that the stream cannot flow toby-pass but this does not occur until one of the lines to a collectingtrap A, B, or C, etc., is open.

Assuming that the by-pass valve 68a is being held open by cam 181, whena sample component comes along from the column, which produces a peak onthe recorder, the pen which traces the record on a chart closes aswitch. By this means the drive motor 220 is tripped to start turningthe shaft 180 through a half revolution. The turning movement takes onlytwo or three seconds to bring the flat cam surface 182 to the bottom.This turning movement allows the by-pass outlet valve 68a to close butit also indexes the rotary valve 67 to a numbered position. This opensthe collector or trap valve to permit gas flow through one of thecollection traps, for example, trap A. In this position, for trap A,assume that the valve is indexed to position 1. Gas will flow throughthis tr-ap A as long as the cam follower 192 is in its raised, closedposition. The details of valve 67 will next be explained.

The indexing valve itself is mounted on the shaft 201 previouslymentioned. It bears and is driven by the gear 186 through means of thegear train described above. Through a connection 205, FIGURE 7, U-shapedline 209 connects the valve 68:: with the chamber formed in part bystationary valve plate member 210 mentioned above, as indicated inFIGURES 4 and 7. The stationary valve member 210 forms the left part ormember of a valve chamber 212, FIGURE 7. It is mounted concentricallywith shaft 201 and bears the connections 205a or 205b, 2050, etc., whichcouple with lines 170, 170a, 170b, etc.,

previously mentioned. This plate 210 cooperates with and is spacedslightly from an opposing but rotating plate 211 which is keyed to thedrive shaft 200 by means of a pin 213. The latter forms the other halfof the valve chamber. Annular sealing rings 214 and 215 are placedbetween plates 210 and 211 to provide the sealed chamber between the twoplates. For the greater part of its periphery the plate 211 is providedon its left or chamber side with a groove 217 concentric with its axis.This groove, however, is interrupted at one point for a short distance,about 15 to 20 of the circumference. The interrupted or cam surface thusprovided serves as an actuator for spring pressed ball valves indicatedat 216. A valve 216 is provided in each connector 205a, etc. Each ofthese valves is adapted to be operated, through an intermediate camfollower ball 218, when pressed to the left, as seen in FIGURE 7. Thus,when the valve plate 211 is indexed to a stop position, the interruptedportion of the groove 217 presses a normally free floating ball 218 tothe left. The normally free ball 218 pushes its adjacent spring pressedball 216 off its seat. That particular ball valve 216 will thus beopened. This opens the flow of gas from the appropriate collector trap,allowing carrier gas to enter the cold collecting chamber where thecomponent is condensed to a liquid and drops to the bottom of the traptube A, etc.

Since the single revolution electric motor 220 and its control clutch221 are of conventional type, it is sufficient to say that when a peakis reached by the recorder, due to movement of the recorder pen, themotor is released for an operation cycle. This drives the cam shaft 191through a half revolution. This causes cam 181 to close the valve 68a bymeans of its follower 192 and hence the gas must flow through one of theconnecting lines 690 or 6%, etc., and one of the valves 216 and outthrough U-shaped line 209 to discharge line 68c. For each peak thatcomes along, valve 67 indexes to the next trap collecting position, I,2, or 3, etc., as the case may be. The revolution is completed toby-pass after the peak is passed and the by-pass valve 68a is againopened when the cam comes to rest with its rounded portion above the camfollower 192.

The parts just described are mounted in a frame consisting of sideplates 240, 241 and end plates 242 and 243 appropriately fastenedtogether. Plate 241 is a relatively heavy one and constitutes the mainsupport for the indexing valve mechanism. Mounted on posts 244 and 245,etc., attached to plate 241 is an intermediate plate 246 which supportsthe shafts and 201 and the intermediate gearing 183, 184, 185, 186,providing the drive previously described. The intermediate gears 184,185 are mounted on a stub shaft 185a supported in journal bearingsformed in plates 241 and 246. Shafts 180 and 201 are supported in plates240 and 241.

The motor 220 and cyclic clutch and control mechanism 221 are mounted ina subframe assembly 250- secured to the plate 241, on the left sidethereof as seen in FIGURE 4.

Referring now to FIGURE 8, the oven 31 which contains the columns isshown in vertical cross section. It comprises insulating front and rearwalls 260, 261, with an insulated base 262 and a partly insulated topcover 263. An intermediate partition is provided, as shown at 264, andone or more blowers 265, preferably two, each driven by a motor 266mounted outside the casing, fits within the bottom part of the oven.Although two blowers are preferably used, a description of the use ofone will sufiice. The blower is so arranged that air is circulated fromthe front part of the oven, at the right "as seen in FIGURE 1,downwardly and up behind the partition 264 in the manner indicated bythe arrows. The columns, 30, 30a, etc., are not shown in detail but arelocated in space 266. A rockable damper 267 hinged on a pivot shaft 268is mounted for partial rotation to open and close positions so that theblower can be used to draw in ambient air through an opening 269 whenthe it I damper is turned to the position shown in FIGURE 9. Forheating, the blower is closed, as shown in FIGURE 8. Hence the sameblower can be used for circulating hot air within the oven or fordrawing in cool air and reducing the temperature.

A series of electric heaters 276, 2T1, 272,273 and 274 is provided inthe rear compartment. They are controlled by adjustable thermostaticmeans including a power proportional controller. This device is of knowncommercial type and need not be described in detail. Obviously, bypassing the air over these heaters and recirculating as in FIGURE 8, thetemperature of the oven can quickly be brought to the desired level. Thecombination of adequate heating means and air circulating means, plusthe damper mechanism which facilitates circulation of cooling air atappropriate times, effects the quick control over temperature which ishighly desirable for the chromatographic separating operation.

The small analytical column may also be mounted in the oven and itis'shown at 51 behind the main columns in FIGURE 2. In the specificexample mentioned above, this column is a A inch tube, ordinarily of theconventional packed type, which can be used for comparative analysisalongside of the larger preparatory scale columns.

Typical results obtained by the apparatus are illustrated in thechromatograms of FIGURES 10A to 10H, respectively. They show the effectof sample size on resolution. These runs were made with three 8 footcolumns connected in parallel. Samples were injected at a temperature of120 C. and the oven temperature was programmed up to 190 C. for eachsample injected. The volume of samples was varied, as shown in theseveral figures. Good resolution was obtained for sample volumes up toabout 4 cc. of sample. At higher sample volumes the first two componentsseparated were not suificiently resolved for eitective collectionalthough separation of the other two components was adequate up tovalues as great as 9 cc. sample size. The extraneous small side peaks onthe latter components did not represent impurities in the sample butwere caused by imperfect matching of the pressure drop across the threeparallel columns. By use of a very precise pressure-drop adjuster, whichmay be incorporated in each of the columns, these peaks can be easilyeliminated. This adjuster is described and claimed in a copendingapplication. It involves a screw threaded pressure-drop mechanism, whichpasses the gas along a slender spiral path provided between matchingscrew threads. By simple adjustment of one or more of these, theparallel columns can be very closed matched. However, even withappreciably mismatched columns, the collection of the individualcomponents is not substantially impaired.

The function of cutting oil clean components for separation iscontrolled by the recorder switch 321s. See FIGURE 11 and furtherexplanation below. This switch, operated by the recorder pen 321p, isadjustable and may be set at a point to cut off only the clear upperparts of the peaks. In the case of FIGURES 10A to lQl-l the recorderswitch was set at 25 percent of the scale, that is, the peak wasintercepted when the lower 25 percent in height of the peak had passedthe recorder. Only that portion of a component which was passing throughand which was confined between the vertical line intercepts with thepeak graph at the selected level (25 percent level in this case) wascollected.

In FIGURE 11 the principal controls are shown, some of them onlydiagrammatically. Electrical connections, in general, are not shown indetail. It is believed that these will be obvious from the followingdescription.

These controls comprise the master power switches 36!, and heatercontrols 303 and 365 for the injection port and for the back pressurevalve 33, respectively. The automatic injector (dispenser 28) iscontrolled electric-ally by the switch 399 which has three positions. Inposition 0, the injector is inoperative. In upper posi tion A, theinjector works automatically in the manner previously described. Bymanually turning the switch down to position M the operator can inject asample (of volume determined by the setting of the micrometer screw ofthe injector) at any time. This affords a convenient method of injectingreproducible samples during manual operation;

The oven temperature programmer and controller is shown at 31d. It is ofcommercially known type and is represented only conventionally. Thecontroller is of the proportional type. It controls simultaneously thetemperatures of all of the heaters in oven 31. The temperature which thecontroller will maintain in the oven is determined by the setting of apotentiometer. A temperature sca e is calibrated to guide the operatorin setting the potentiometer. It is preferably calibrated in incremeritsof 5 C, e.g., from 25 to 325 C.

The temperature is programmed by driving the potentiometer upscalethrough a set of gears. These gears are not shown but they are soarranged for shifting gear ratios in order that various ratios oftemperature change may be obtained. An electric motor of an suitabletype drives these gears, under control of a programmer switch.

The programmer switch can be set to any of three positions, viz.,automatic program, i othermal, and off. Upper and lower temperaturelimits for a programmed run are determined by shifting limit switchesLS1 and LS2 along the path of the temperature indicator 314E which runsalong a predetermined path 3MP.

The switch 313 controls the input leads to the recorder 321. SeeFIGURE 1. As previously mentioned, these leads may be reversed to assurepositive peaks on the recorder during preparative operations (positionP) or analytical operations (position A). The third position B by-passesthe carrier gas around sample reservoir 28b so that it can be refilled.

Three delay timers are shown at 315, 31% and 317. Timer 3l5 can be usedduring both isothermal and programrned automatic runs. It allows a delayof up to 15 minutes between the end of one run and the injection of thenext sample. This allows sufiicient time for establishment oftemperature equilibrium at the lower temperature limit after aprogrammed run. It also allows time to clear the column of any remainingsample material during isothermal operation.

Timer 316 is provided to delay the temperature programming of the ovenfor a period of time up to 15 minutes after a new sample is injected.This is useful to permit stripping solvents off the main sample, whensuch is desirable. This may save operating time by decreasing the totalprogrammed temperature range. Timer 316 is called the post-injectiondelay timer. It is used only during automatic programmed temperatureoperatron.

The timer 317 is the upper temperature delay timer. It also is employedonly during automatic programmed operation. It allows the columntemperature to be held isothermally at the upper temperature limit for adesired period of time, up to 15 minutes, before the column is cooleddown (by opening the damper 267, etc.) to start another cycle. Thisprovides another means for making certain that the column is cleared ofsample material before the neXt run.

An attenuator 32%) is provided to divide the input signal to therecorder in successive steps. The first step divides by 2, the next by4, the next by 8, etc., up to the last step which has an infinitedivider, i.e., the signal is completely attenuated.

The recorder 321 is of commercial type and represents graphically theseparated components by peaks on a chart. These peaks are recorded by amarking pen which is kept in contact continuously with a slowly movingrecord strip. As previously mentioned, a switch 3215 can be set atvarious positions on the scale, to be contacted by the recording pen321? at the desired point on this scale.

aaevgeae 13' The setting of this point represents an indicatedpercentage of the full scale. As a component passes through the detectorthe pen starts upscale (across towards the right as seen in FIGURE 11).When it reaches the relay set point it causes switch 3215 to activatethe mechanism which indexes valve 67 to its next collection position.The valve stays in this position until the pen passes the switch on itsdown scale run. The valve 67 is then indexed to the next by-passposition. Only that part of the component represented by the peak areaabove the set points is collected. The relay switch 3218 can be set atany point but is usually set between the and 95% limits. See shaded areaRA, FIGURE A.

Switch 322 controls the oven damper 267 and has three positions. Itoperates by controlling the gas supplied to cylinder 76, FIGURE 1, whichoperates the oven damper by a pneumatic piston. One position of theswitch opens the damper, another closes it, and the third positionplaces it under control of the temperature programmer mechanism 314,etc., described above.

A switch 323 turns on the power to the oven temperature controller 314,etc. Switch 324 turns on the power to the blowers in the oven. Theblowers must be on whenever the oven heaters are on to prevent localoverheating.

Valve 67 can be manually controlled by a knob 331 aflixed to cam shaft180. By this means the valve 67 can be indexed by a 30 step whenever theoperator desires. This is accomplished by turning the shaft 180 through180. A switch 332 also is provided to determine the type of operationfor the indexing collection valve 67. It permits manual operation onlywhen in its center position. The upper position is for isothermaloperation and the down position'for automatic programmed temperatureoperation.

Pointer 333 indicates the position of the collection valve 67. It isalways in the starting or zero position when injecting a sample forautomatic operation. Swtch 334 is a control device for bringing thevalve 67 back to starting or zero position after the desired number ofcomponents has been collected from a given sample. Elution of the lastpeak, as seen by the recorder, controls re-injection during automaticoperation. Hence it is set for the maximum number of components (notexceeding 6 in this particular apparatus).

To recapitulate the operation briefly, a reference analysis is normallymade first by passing a small sample of the material to be separatedthrough the analytical column 51. After the reference has beenestablished at the detector, carrier gas is passed through the largercolumn or column assembly 30. Samples of predetermined size aredispensed by the injector and forwarded to the injection port 29. Herethe sample material joins the carrier gas. Separation of components ofthe sample occurs in the column 30, being facilitated and controlled byvarying the oven temperature, according to a predetermined program.

As long as carrier gas alone is effluent from the column, in normalautomatic operation, the stream passes to the bypass line 68a. Cam 181is stationary and its follower is in the depressed position under theraised cam portion. As soon as a component peak arrives at the detector35, and the peak rises to the predetermined point on the recorder, wherethe pen is set, the pen closes control switch 3218 to trip the cyclicmotor and clutch mechanism through one cycle. This cycle runs just longenough to rotate cam shaft 180 through 180. As the cycle is completed,cam 181 allows the by-pass valve to open under flat cam portion 182. Thevalve 67 is indexed from the by-pass position through 30 to the firstcollection point. This opens the ball valve (by means of cam surface217) and allows gas to flow out of the collection trap A. The valvesremain in this position until the recorder pen again trips switch 3218on its way down the peak. When this occurs, the cam shaft rotatesanother half revolution, the indexing valve moves through another 30 andthe spring ball valve is closed. Meanwhile, cam 181 has again opened thebypass valve 68a. When the next component peak comes along, the valve 67is indexed to the next collecting station or position, etc.

It will be obvious that various modifications may be made in theapparatus and in the manner of operating it. It is intended to coversuch modifications and changes as would occur to those skilled in theart, as far as the following claims permit and as far as consistent withthe state of the prior art.

What is claimed is:

1. In a chromatographic separator of the type which comprises aseparating column for separable componentcontaining sample material, andplural collecting means for collecting separated components of saidmaterial, the improvement which comprises:

a common manifold means for simultaneously conveying said separatedcomponents to all of said collecting means;

a multi-position indexing valve located downstream of said manifoldmeans, having a separate valve inlet from each of said collecting means,by-pass inlet means from said manifold by-passing said valve inlets, andan output means connected for fluid flow from any of said inlets andfrom said by-pass inlet means;

and means for indexing said valve alternately between a different one ofsaid separate inlets and said bypass inlet means, whereby each of theparticular separated components of said material is passed to adifferent collecting means and contamination of the valve by suchcomponents is reduced.

2. The combination set forth in claim 1 which includes a separatecollecting means between said by-pass inlet means and said manifoldmeans thereby to further reduce contamination of the valve by thecomponents of said sample material.

3. The combination set forth in claim 1 wherein said manifold means isheated to maintain said sample components vaporized.

4. The combination set forth in claim 1 wherein said collecting meansare maintained at a sufiiciently low temperature to condense said samplecomponents.

5. The combination set forth in claim 1 wherein said manifold includesmeans for preventing fluid circulation between said collecting means.

6. The combination set forth in claim 5 wherein means \for preventingfluid circulation includes a unidirectional flow means with flow pathconnected between each collecting means and said manifold means.

7. The combination as set forth in claim 1 wherein said indexing valveincludes means for continuously maintaining a flow path through one ofsaid inlets, thereby to avert significant flow rate variations in thechromatographic separator.

8. The combination as set forth in claim 7 wherein said indexing valveincludes means for establishing a new flow path through one of saidinlets before blocking an existing flow path through another of saidinlets.

9. The combination as set forth in claim 1 which includes a separatecollecting means between said by-pass inlet means and said manifoldmeans thereby to further reduce contamination of the valve by thecomponents of said sample material and wherein said manifold meansincludes means for preventing fluid circulation between said collectingmeans.

10. In a chromatographic separator of the type which comprises aseparating column for separable componentcontaining sample material, andplural collecting means for collecting separated components of saidmaterial, the improvement which comprises:

a common manifold means for simultaneously conveying said separatedcomponents to all of said collect ing means;

a rnulti-position indexing valve having a separate valve inlet from eachof said collecting means, by-pass inlet means'from said manifold, and anoutput means connected for fluid flow from any of said inlets;

and means under control of eluent material from said separator forindexing said valve alternately between a different one of said separateinlets and said by-pass inlet means, whereby each of the particularseparated components of said material is passed to a dififerentcollecting means and contamination of the valve by such components isreduced.

11. In a chromatographic separator of the type which comprises aseparating'column for separable componentcontaining sample material, andplural collecting means for collecting separated components of saidmaterial, the improvement which comprises:

a common manifold means for simultaneously conveying said separatedcomponents to all of said collecting means;

a multi-position indexing valve having a separate valve inlet from eachof said collecting means, by-p-ass inlet means from said manifold, andan output means connected for fluid flow from any of said inlets;

means under control of eluent material from said column for indexingsaid valve alternately between a difierent one of said separate inletsand said by-pass inlet means, whereby each of the particular separatedcomponents of said material is passed to a different collecting meansand contamination of the valve by such components is reduced;

and automatic means for injecting new and identical sample quantitiesover an extended period of time into said column whereby substantialquantities of each of the separated components maybe collected intoseparate collecting traps under the control of said indexing valve.

12. The combination set forth in claim 11 wherein said valve includesmeans for establishing a new flow path through one of said inlets beforeblocking an existing flow path through another of said inlets.

13. A component collection system for a preparative scale gaschromatograph of a type capable of separating multiple components fromsample material supplied thereto, said system comprising, incombination:

a chromatograph;

a manifold for receiving efiiuent including the separated componentsfrom the chromatograph; exhaust flow means for venting said manifold;

means for maintaining the temperature of said manifold at a level toprevent condensation of any of said components;

first and second individual collecting traps each having inlets andoutlets;

means for continuously flow connecting all of said trap inletsdownstream of said manifold;

means for maintaining said traps at a temperature to causecondensationof the sample components to be collected;

valve means on each of said outlets for controlling the flow of theetliuent through said traps; additional valve means on said exhaust nowmeans for controlling the flow of the effiuent thcrethrough; and meanscontrolled by the efiluent components for sequentially actuating each ofsaid valve means and said additional valve means to collect a differentcomponent in each of said traps and by-pass the remainder of theefiluent away from the traps.

14. A component collection system for a preparative scale gaschromatograph of a type capable of separating multiple components fromsample material supplied thereto, said system comprising, incombination:

a chromatograph;

a manifold for receiving effluent including the separated componentsfrom the chromatograph;

means for maintaining the temperature of said manifold at a level toprevent condensation of any or" said components;

first and second individual collecting traps each having inlets andoutlets;

means for continuously flow connecting all of said trap inletsdownstream of said manifold;

means for maintaining said traps at a temperature to cause condensationof the sample components to be collected;

valve means on each of said outlets for controlling the flow of theefiiuent through said traps; and

means associated with the inlets of each trap for preventing circulationbetween individual ones of said traps.

References tilted by the Examiner UNITED STATES PATENTS 2,963,89812/1960 Reynolds 7323.1 2,981,092 4/1961 Marks 5567 X 3,002,583 10/1961Findlay 5567 X 3,063,286 11/1962 Nerheim 7223.1

3,124,952 3/1964 Johnson 73'23.1 3,185,211 5/1965 Crawford et al. 5567 XOTHER REFERENCES Atkinson, E. P., and Tuey, G. A. P., An AutomaticPreparative Scale Gas Chromatograph Apparatus. in Gas Chromatography,1958, ed. by D. H. Desty, London, Butterworths Scientific Publications,1958, pp. 284, 285.

REUBEN FRIEDMAN, Primary Examiner.

'C. N. HART, Examiner.

1. IN A CHROMATOGRAPHIC SEPARATOR OF THE TYPE WHICH COMPRISES A SEPARATING COLUMN FOR SEPARABLE COMPONENTCONTAINING SAMPLE MATERIAL, AND PLURAL COLLECTING MEANS FOR COLLECTING SEPARATED COMPONENTS OF SAID MATERIAL, THE IMPROVEMENT WHICH COMPRISES: A COMMON MANIFOLD MEANS FOR SIMULTANEOULSY CONVEYING SAID SEPARATED COMPONENTS TO ALL OF SAID COLLECTING MEANS; A MULTI-POSITION INDEXING VALVE LOCATED DOWNSTREAM OF SAID MANIFOLD MEANS, HAVING A SEPARATE VALVE INLET FROM EACH OF SAID COLLECTING MEANS, BY-PASS INLET MEANS FROM SAID MANIFOLD BY-PASSING SAID VALVE INLETS, AND AN OUTPUT MEANS CONNECTED FOR FLUID FLOW FROM ANY OF SAID INLETS AND FROM SAID BY-PASS INLET MEANS: AND MEANS FOR INDEXING SAID VALVE ALTERNATELY BETWEEN A DIFFERENT ONE OF SAID SEPARATE INLETS AND SAID BYPASS INLET MEANS, WHEREBY EACH OF THE PARTICULAR SEPARATED COMPONENTS OF SAID MATERIAL IS PASSED TO A DIFFERENT COLLECTING MEANS AND CONTAMINATION OF THE VALVE BY SUCH COMPONENTS IS REDUCED. 